Me too!!! (Wish I could see the future…)
Sorry I could not resist to that.
Formats, well, you have at least one: PDF/A (Standard ISO-19005-1).
It’s designed exactly to guarantee that any file compliant with it is self sufficient and can be read in any hardware and software platform existing 30, 100, you name it years from now.
More info in:
http://en.wikipedia.org/wiki/PDF/A
or
http://www.pdf-tools.com/public/down...paper-pdfa.pdf
Problem: none of today’s readers let us read these files totally without a problem.
Once this is resolved… this can be a sustained solution, as PDF/A is a “Electronic document file format for long term preservation”.